X-linked muscular dystrophy caused by a nonsense variant in the DMD gene, leading to absence of dystrophin and progressive muscle degeneration. It was described in two Maine Coon siblings with muscle hypertrophy, growth retardation, weight loss and vomiting, with markedly elevated serum creatine kinase. Molecular testing allows identification of affected males and carrier females.

Initially described in two Maine Coon siblings (Beckers 2022). The authors did not detect the variant in the population databases consulted (99 Lives, EVA), so it is considered rare: limited data.

- Muscle hypertrophy (especially of the axial musculature and the tongue)
- Growth retardation and weight loss
- Vomiting
- Markedly elevated serum creatine kinase
- Progressive weakness and muscle degeneration
- Absence of dystrophin on muscle biopsy

Beckers et al. (2022) first described Duchenne muscular dystrophy in two Maine Coon siblings. Using mRNA sequencing they identified a nonsense variant in exon 11 of DMD (c.1180C>T, p.Arg394*) and established perfect X-linked segregation in the pedigree. Immunohistochemistry showed absence of dystrophin. Other feline DMD variants were previously known, including the classic deletion of the muscle promoter causing feline hypertrophic muscular dystrophy, and in 2024 a new variant was described in a domestic shorthair cat.

- Do not breed affected males or carrier females without genetic counselling.
- Identify carrier females by molecular testing before breeding.
- A healthy male born to a carrier mother may be used (males receive the maternal X); a female must be tested before breeding.

Suspect in a male cat with muscle hypertrophy, markedly elevated CK and progressive weakness. Confirm with electromyography, histopathology and dystrophin staining. The prognosis is guarded and management is supportive; there is no curative treatment. Differential diagnosis with classic feline hypertrophic muscular dystrophy and other myopathies. Genetic counselling of carrier queens is essential.

1. Beckers E, Cornelis I, Bhatti SFM, et al. A Nonsense Variant in the DMD Gene Causes X-Linked Muscular Dystrophy in the Maine Coon Cat. Animals (Basel). 2022;12(21):2928. PMID: 36359052.
2. Shelton GD, Tucciarone F, et al. Precision medicine using whole genome sequencing identifies a novel dystrophin (DMD) variant for X-linked muscular dystrophy in a cat. J Vet Intern Med. 2024;38(1). PMID: 38180235.
3. OMIA:001081-9685. Muscular dystrophy, Duchenne type in Felis catus. https://omia.org/OMIA001081/9685/